Hello Ashish !
Thank you for posting on Microsoft Learn Q&A.
Integrated Vectorization in Azure AI Search is designed for documents in OneLake Files (PDF, DOCX, TXT, HTML, images to OCR...).
Your lakehouse show data under tables and the wizard won’t pull rows from lakehouse tables and turn them into content automatically, so your indexer finishes with 0 documents.
You can put your documents under lakehouse then files or add a OneLake shortcut there.
In the wizard, choose OneLake (Fabric) and browse to the files path then keep integrated vectorization on so it will extract text then embed then store vectors.
Then give your search service managed identity reader on the Fabric workspace or the Lakehouse item and if you use a user assigned MI, grant that principal access.
You can also use text-embedding-3-small/large instead of text-embedding-ada-002.